Make sure that the bolt pin is in the groove on the hammer and not in front or behind it.  Pull the pin and look in the top slot and you'll see what I am talking about.  Line up the hole in the bolt that the pin goes through and slide the pin in.  You should feel the drag of the hammer assembly when you move the bolt/pin back and forth.  Pull the bolt/hammer assembly back and air up.  Still leaking?

That is a common cause for a leak down the barrel.  In the manuals section here on I-O, I also found that a dirty valve is listed as a possible air down the barrel cluprit.  http://www.impulse-owners.com/manuals/impulse-cricket_manual.pdf

Not being a Cocker person I can't say, but that sounds right.  Most leaks are o-ring or grunge related.  If there is a solenoid leak, there are gaskets there too.  Buy it up and give it some lovin' and it will treat you well.  Go up on e-bay to see what they are selling for.  Not lots of cash depending on the ups.  Enjoy and stay on the site to give us updates and post a photo of your new toy.

yes, leak down the barrel is very common and can easily be fixed. i wouldnt let that stop me from buying it. But i'd sure figure that into my offer price!